1. Field of the Invention
The present invention generally relates to an image processing method, and more particularly to a mirror image suppression method adapted to an optical coherence tomography (OCT) system.
2. Description of Related Art
In the application of Fourier-domain OCT technology, how to suppress mirror image signals of a tomography image to improve the image quality is an important subject to be solved. The mirror image in the tomography image is caused by incomplete information of reverse Fourier transform in a single A-mode scan. In the prior art, phase-shift algorithm is used in combination with a piezoelectric transducer (PZT) to suppress the mirror image. However, such a method requires a phase shift generation mechanism, to achieve the purpose of suppressing the mirror image by generating phase shift between different A-mode scans. Furthermore, an electro-optical modulator (EOM) is also used to suppress the mirror image. In the method, multiple times of A-mode scans must be performed on a same lateral position to achieve the purpose of suppressing the mirror image, resulting in the decrease of an image capture speed and the generation of a motion artifact. However, elimination of these disadvantages may cause the construction of an imaging system to become complex and expensive. In addition to the suppression of the mirror image by using the concept of phase modulation, the mirror image may also be suppressed in a frequency-shift manner by using an acousto-optic modulator (AOM), an EOM, and a dispersive delay line in the prior art.
However, in the prior art, partial loss exists no matter the mirror image is suppressed by using the concept of phase modulation or in the frequency-shift manner. Therefore, it is necessary to provide an effective mirror image suppression method.